Dave - Sorry I doubted you. YES, YES, YES, I can trust SD!. Deleting the MP3's was my fault. I can't explain how iTunes directory location got changed to the BACKUP location but it did. Then when I added new MP3's they were getting added to the BACKUP hard drive and when SD! ran it copied the three week old files from the MAC hard drive and wrote over the "new" MP3's on the BACKUP hard drive. If anyone needs further details I will gladly supply screen shots and explanation. This is a good product and has performed flawless for 6 months. I've got 50GB of music, 10 GB of photos and 9 GB of other data. All safe and sound thanks to Super Duper!